The Callaghan family can't believe they're getting all this attention for something they've been doing for years. He says it only takes 15 minutes to pack his daughter's lunch. Counting since kindergarten, that's about 1,600 meals. Each time, he tried to make it special.

"Sometimes it was a cookie, or sometimes it was a piece of candy," said Callaghan, but most of the time, there was a note, written on a white napkin. "They said things like, 'I love you,' 'Have a great day,' 'Be a good friend."

"It's really important. It's nice to know he's thinking about me," said his daughter Emma Callaghan, now 14 years old. "It's nice to have a piece of him with me at school."

As Emma got older, the notes became more personal and creative, including quotes and codes. Then Emma, went to sixth grade.

"That was the first time I was diagnosed with cancer," said Garth.

And the notes took a deeper meaning.

"They could, in fact, be something that Emma would have that would be tangible, that she could hold onto in the event that things didn't work out well," said Garth.

Diagnosed with kidney cancer, Garth opted for surgery. He also noticed that Emma started ripping the quotes from the napkins and keeping them in a composition book. She says it was a way to keep a piece of her dad with her.

The recovery went well, until one year later.

"In August of 2012, I was diagnosed with prostate cancer," he said.

Doctors say it's slow-growing, but he must live with it and get it checked regularly.

Then, a third blow just last year, kidney cancer again.

"[The doctor] looked at me and he said, 'Mr. Callaghan, you are going to die from this," said Garth.

Then the sobering statistic: a patient with his health history has a ten percent survival rate of five years, which means there is a chance he may not see Emma graduate high school. It's a tough conversation for any family.

"I don't remember the actual conversation, but I know it started, 'I'm not going to die from this,'" Emma said.

Garth says he's determined to beat the odds, but he did calculate this: 826 school days until his daughter's graduation, so he made this promise.

"To write out 826 napkin notes ahead of time, so in the event that I wouldn't be around to hand them off to her in her lunch, they would still be available," said Garth.

It took a month, but he made it happen. In each note, he hopes Emma will hear his voice.

Garth say he has no symptoms from the cancer and he's not suffering, but the story of his promise has now become an inspiration to parents around the world. The family even made a trip to New York and appeared on several morning shows, inspiring others with this simple act.

"I won't be satisfied until every parent is writing a note to their child somehow, some way," said Garth.

It's a bond he wants other families to know.

Recently, it all came full circle when this note came from his daughter, written on a paper towel:

If all my friends really did jump off a cliff, it's because it was my idea. Your daughter is a leader not a follower.

PS I think you used all the napkins.

Garth says he plans on presenting Emma with all 826 notes on her high school graduation day. He also promised he won't embarrass her.